All measured data is in principle prone to error and in many cases, continuous availability of the measured data is not provided. Aside from the dependence of measured data on sensor-inherent properties, the measured data is also frequently dependent on environmental conditions. Sensor errors or measurement errors can here be divided into quasi-stationary portions which are constant over several measurements, such as a so-called offset, and statistical portions, which arise randomly from measurement to measurement, such as background noise. While the random portions cannot in principle be corrected deterministically, the quasi-stationary errors can in general be corrected if monitoring is possible. Non-correctable significant errors can usually be at least avoided if they can be detected.
In the prior art, sensor fusion methods are already known in this connection, which are usually also suited for correcting or filtering measured data of different sensors or sensor systems. In the automobile industry in particular, particular standards need to be observed here, since a plurality of different sensors senses a shared environment situation or motor vehicle state by means of different measuring principles, and describes this environmental situation or this motor vehicle state by means of a plurality of different measured data. For a sensor fusion that can be used in the automobile industry, the greatest possible degree of robustness is therefore required against random interferences, as is a detection and compensation of systematic errors. Equally, time influences on the measured data must be corrected and temporary failure or the non-availability of sensors must be bridged.
DE 10 2012 216 211 A1 describes a method for selecting a satellite, wherein the satellite is a satellite of a global navigation system. Before such a satellite is used for determining a position or a vehicle, the received GNSS signals are verified in different ways. For this verification, two different redundancies or known contexts are exploited in each case. Thus, DE 10 2012 216 211 A1 discloses, for example, the determination from the signal of a satellite of both the distance of the vehicle to the satellite and the relative speed of the vehicle in relation to the satellite. The distance can here be determined by means of the runtime of the signal, while the relative speed can be determined by means of phase measurement of the signal. Since the distance and the relative speed depend on each other, they can be verified against each other. Further, a verification can be conducted of the values determined from the signal against known framework conditions, since a vehicle usually progresses within a certain speed range. Also, it is described that when receiving several signals from different satellites, the distances to several satellites are determined and these distances are at the same time verified using trigonometric contexts and the known distances of the satellites in relation to each other. Finally, verification is also possible of the distance determined from the signal, or of the speed determined from the signal using other sensors, which also permit a determination of the position or a determination of the speed. If the signals of a satellite cannot be verified, this satellite is not used to determine the position or to determine the speed.
A sensor system comprising several sensor elements is known from DE 10 2010 063 984 A1. The sensor elements are designed in such a manner that they at least partially capture different primary measured values and at least partially use different measurement principles. Further measured values are then at least partially derived from the primary measured value of the sensor elements. Further, the sensor system comprises a signal processing facility, an interface facility and several function facilities. The sensor elements and all function facilities are here connected to the signal processing facility. The primary measured values therefore deliver redundant items of information which in the signal processing facility are compared with each other or which can mutually support each other. From the comparison of the observables calculated in different ways, conclusions can be drawn about the reliability and precision of the observables. The signal processing facility qualifies the precision of the observables and makes the observables available to different function facilities, together with a statement regarding the precision via an interface facility.
DE 10 2012 219 478 A1 discloses a sensor system for the independent evaluation of the integrity of its data. The sensor system is preferably used in motor vehicles and comprises several sensor elements which are designed in such a manner that they at least partially capture different primary measured values or at least partially use different measurement principles. The sensor system further comprises a signal processing facility which at least partially jointly evaluates the sensor signals and at the same time evaluates the information quality of the sensor signals. The signal processing facility additionally provides an item of information about the contradiction freedom of at least one date of a physical value, wherein the date of the physical value is calculated on the basis of the sensor signals from sensor elements, which either directly capture the physical value or the physical value can be calculated from its sensor signals. The information about the contradiction freedom of the date is now calculated on the basis of directly or indirectly redundant sensor information provided.
The generic methods and sensor systems which are known in the prior art are however disadvantageous in that no account is taken of the environment-dependent or situation-dependent availability of the correction measurements. Even the total failure of certain systems is often not taken into account. This leads to non-optimal results of the merged and corrected data.
The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.